# Program name: ad_choose_and_show.pl
# Type: include file for perl programs
# Author: Rajiv Pant (Betul)   betul@rajiv.com   http://rajiv.org

# Version: 1.2. Updated for Perl 5. 1996/Sep

# TO DO: Convert to .pm Perl module or Java
# TO DO: use global datafile of ads related to words not local.

srand (time | $$) ;

sub ad_choose_and_show
{
my $WWW_URLs    = 'http|https|mailto|ftp|telnet|gopher|wais|news|snews' ;

my $DocumentRoot        = '/web' ;
my $AdsRoot             = 'advts' ;     # relative to DocumentRoot
my $ad_data_dir         = 'data' ;      # relative to AdsRoot
my $ad_images_dir       = 'images' ;    # relative to AdsRoot


my $ad_logging_program_relative_url = '/programs/ads-to-go' ;

my ($ads_dir, $number_of_ads_to_show, $how_to_show) = @_ ;
my $ads_dir_path                = "$DocumentRoot/$AdsRoot/$ads_dir" ;

my $err ;

(-d $ads_dir_path) || ($err.=<<EOM
<!-- the "$ads_dir" folder not found inside AdsRoot. -->
EOM
) ;

chdir   ($ads_dir_path) ; # TO DO: save current dir and return before exit

my @ads ;

(opendir (DIR, $ads_dir_path)) ?
(@ads = grep (/\.data$/oi, grep (-f, readdir(DIR)))) && closedir (DIR)
: ($err .=<<EOM
<!-- the "$ads_dir" folder inside AdsRoot could not be opened. -->
EOM
) ;

my @ads_left = @ads ;

my ($i, $ad_data, $ad_image, $ad_url) ;

for ($i = 1 ; $i <= $number_of_ads_to_show ; $i++)
{

$ad_data        = $ads_left[rand($#ads_left+1)] ;
$ad_image       = $ad_data ;
$ad_image       =~ s/\.data$/.gif/ ;

$err = '' ;

$ad_data || ($err .=<<EOM
<!-- the "$ads_dir" folder inside AdsRoot does not contain ad data files. -->
EOM
) ;

(open (ADDATA, "$ads_dir_path/$ad_data")) || ($err .=<<EOM
<!-- the ad data file "$ad_data" in the "$ads_dir" folder under AdsRoot could not be opened. -->
EOM
) ;

my ($l, $alt_text) ;

while (chop ($l = <ADDATA>))
  {
($l =~ /^$WWW_URLs:/) && ($ad_url = $l);
($l =~ /^alt=/) && ($alt_text = $l) && ($alt_text =~ s/(^alt=|[^\w\s\[\]])//g);
  }
close (ADDATA) ;

$ad_url || ($err .=<<EOM
<!-- a valid url could not be found inside ad data file "$ad_data" -->
EOM
) ;


my ($width, $height, $type) = 
&gifsize ("$DocumentRoot/$AdsRoot/$ad_images_dir/$ad_image") ;

($type eq 'GIF') || ($err .=<<EOM
<!-- file "$ad_image" is not in gif format -->
EOM
) ;

(($width < 3) || ($width > 600) || ($height < 3) || ($height > 600))
 && ($err .=<<EOM
<!-- unacceptable size for "$ad_image" width=$width height=$height -->
EOM
) ;


if ($how_to_show eq 'image')
{
        print <<EOM;
Content-type: image/gif

EOM
        local *IMAGE_FILE ;
        my $buffer ;
        open IMAGE_FILE, "$DocumentRoot/$AdsRoot/$ad_images_dir/$ad_image" 

        or $err .= <<EOM;
Ad image $DocumentRoot/$AdsRoot/$ad_images_dir/$ad_image not found.
EOM

        if ($err)
        {
        print $err ;
        exit ;
        }

        else
        {
                while ( read ( IMAGE_FILE, $buffer, 16384 ) )
                {
                        print $buffer ;
                }
                close IMAGE_FILE ;
        }

}
else
{
        $err ? print "\n\n", $err, "\n\n" 
        : (print <<EOM
<a href="$ad_logging_program_relative_url?$ad_url&image=$ad_image"><img border=0 
 src="/$AdsRoot/$ad_images_dir/$ad_image" alt="$alt_text"
 width=$width height=$height></a>
$how_to_show
EOM
        ) ;
}


my @ads_shown_already ;
my $number_of_ads_shown_already ;

$ads_shown_already[$number_of_ads_shown_already++] = $ad_data ;

my ($j, $k) ;

if ($number_of_ads_to_show <= ($#ads+1))
  {
  $j = 0 ; @ads_left = () ;
  foreach $k (@ads)
     {
     $ads_left[$j++] = $k unless (&inarray($k, @ads_shown_already) == 1) ;
     } # eo foreach $k
  } # eo if 

} # end for $i = 1 to $number_of_ads_to_show

} # eo &choose_and_show_ad


sub inarray
{
my ($t, @arr) = @_ ;
my ($tt, $m) = ('',0) ;
 
foreach $tt (@arr)
  {
  ($t eq $tt) && ($m = 1) ;
  }
return $m ;
} # end sub inarray


sub gifsize
{
my ($gif, $w, $w2, $h, $h2, $gifwidth, $gifsize, $type) = () ;
($gif) = @_ ;
open (GIF, $gif) ; read (GIF, $type, 3) ;
seek (GIF, 6, 0) ; read (GIF, $w,  1) ;
read (GIF, $w2, 1) ;
$width  = ord ($w) + ord ($w2) * 256 ;
read (GIF, $h,  1) ; read (GIF, $h2, 1) ;
$height = ord ($h) + ord ($h2) * 256 ;
close (GIF) ;
return ($width, $height, $type) ;
} # eo &gifsize



1 ;